The biochemical basis is being sought for the different adrenal steroidogenic patterns seen in the salt susceptible (S-strain) and the salt resistant (R-strain) rats of Dahl. Specifically adrenal cytochromes P-450 for various steroid hydroxylations will be compared by studying carbon monoxide inhibition of enzyme activity between strains. An attempt is being made to isolate a recently discovered pituitary protein which is unique to R-rats. Effects of this protein on blood pressure and renal water, sodium and potassium excretion will be investigated.